Biotropica最新文献

Endotherms balance high and stable body temperatures against significant energetic costs and food demands. Heterothermy, including torpor, helps individuals balance energy budgets under challenging conditions. Small flying endotherms face considerable challenges when balancing energy budgets during periods of inclement weather with low food availability. Although there is a wealth of knowledge about heterothermic responses of temperate insectivorous bats, considerably less is known about its occurrence and the factors that promote it in nectar-feeding bats from tropical regions. Here, we experimentally tested whether Merriam's long-tongued bat (Glossophaga mutica), a Neotropical nectarivorous species, uses heterothermy in response to reduced energy intake. Using temperature sensitive PIT-tags, we monitored subcutaneous temperature in wild-caught males fed either the full (100%) or restricted (25%) amount of predicted daily energy expenditure. Compared to bats that were fed a full energy diet, energetically challenged bats maintained subcutaneous temperatures significantly closer to roost temperature during the daytime inactive period, indicating a greater heterothermic response. Our results provide further evidence that G. mutica can flexibly modulate body temperature in response to short-term energy deficits. This is similar to patterns observed in other nectarivorous bats, insectivorous bats, and nectar-feeding birds like hummingbirds. This study contributes to a growing understanding of heterothermy in tropical mammals and suggests that nectarivorous bats use heterothermy as an adaptive response to unpredictable food availability likely driven in part by climate change.

We provide the first detailed documentation on the distribution and natural history of the Western Ghats King Cobra, Ophiophagus kaalinga, in Goa State, India, and its interesting apparent interaction with railway infrastructure, which may influence its distribution. The combination of rescue records, verified sightings, local reports, and historical data allowed us to document a total of 47 georeferenced localities where O. kaalinga has been found in the state, with 18 localities in North Goa District and 29 in South Goa District. These data inform our study of the Goa Gap, a biologically significant region without obvious physical characteristics, and assess the suitability of this area for king cobras. Using a series of climate and vegetation variables, we were able to model the potential distribution of the species in Goa. It is noteworthy that the five king cobra records that fall along busy railway corridors had the lowest predicted probability, as predicted by our model. Combined with recent reports of snakes on trains in India and of O. kaalinga in a rail yard, entirely unsuitable reptile habitats, we propose the hypothesis that snakes, king cobras included, may inadvertently expand their ranges by accidental transport on trains.

Studies on habitat fragmentation often evaluate how habitat amount and isolation influence species richness at the local scale, mainly following the Island Biogeography Theory (IBT) framework. Alternatively, the Habitat Amount Hypothesis (HAH) proposes a unifying framework, suggesting that species richness is primarily determined by the total amount of habitat in the landscape rather than by fragment size and isolation per se. We tested this hypothesis using historical data on ant assemblages collected in the experimental area of the Biological Dynamics of Forest Fragments Project (BDFFP) in Central Amazon. Ants were sampled in nine fragments, which varied in size (from 1 to 100 ha) and in the amount of forest in the surrounding landscape. Our results indicate that the amount of forest habitat in the landscape influences species diversity in the fragments, especially among forest specialist species. Additionally, we found that the observed changes in ant species composition between fragments were also associated with differences in landscape forest cover, independently of fragment size. These findings highlight the critical role of habitat availability in shaping ant assemblages and the importance of multi-scale approaches in conservation strategies, particularly in highly diverse and increasingly threatened ecosystems such as the Amazon Forest.

Rapid, human-induced climate change has posed significant challenges to wildlife. One key strategy animals use to cope with environmental temperature fluctuations is behavioral thermoregulation. Understanding how climate change is expected to influence animal behavior is crucial for assessing its impact on species survival and informing effective conservation efforts. Giant anteaters have been found to exhibit conspicuous behavioral responses to temperature changes. Despite their broad thermal neutral zone (15°C–36°C), climate projections indicate that this species is increasingly likely to experience heat stress. We used GPS tracking and continuous-time analyses to investigate how environmental temperature influences the movement ecology of giant anteaters. We integrated our findings with climate change projections to link giant anteater's responses to present weather conditions with those expected under future climate scenarios. Giant anteaters' movement speed exhibited a negative quadratic response to temperature, peaking at 23.7°C. 95% of their movement occurred between 15.0°C and 32.3°C, which aligns with their thermal neutral zone. The increasing temperature led giant anteaters to increase selection for native forests, but had no effect on selection for exotic tree plantations. This shows the importance of native forests as these thermal shelters help to mitigate the negative consequences of high temperatures on anteater's movement. However, the warmer temperatures predicted for Brazil throughout the rest of the 21st century indicate that giant anteaters may experience a reduction of up to 84% in their movement speed. This would hinder the acquisition of sufficient energy resources and threaten the species' persistence. We emphasize the need for conservation efforts that account for the impacts of climate change on species survival and stress the importance of preserving forests as essential refuges that help wildlife to cope with rising temperatures.

Clonality and asexual reproduction in two species of Vellozia Vandelli are reported as the focus point of this interesting Natural History Field Note. It adds Vellozia variabilis and V. tubiflora to a list of species in which aboveground clonality has been formally reported and/or illustrated, namely: V. auriculata (Mello-Silva and Menezes 1999); V. leptopetala and V. epidendroides (Jacobi and Del Sarto 2007); V. dracaenoides and V. compacta (Alves et al. 2014; Alves 2023a, 2023b). The latter two online books may be too recent for the authors to know. Another interesting result of this paper is the relative absence of juvenile specimens in the studied populations, which I also found in my study localities (all of my references herein).

The statement that “this is one of the first records of cloning from aboveground stems in Cerrado plant species” is an exaggeration, as exemplified by Leiothrix flagellaris Ruhland (Eriocaulaceae) (Figueira et al. 2007). Aboveground clonality in the Cerrado is also well known for many bromeliads (e.g., Sampaio et al. 2002); orchids and other epiphytes, several fern species, and some interesting Marcgraviaceae.

From outside the Cerrado, I exemplify some of the crucial works on clonality, including aboveground: Jeník (1994) reviewed clonality (including aboveground) in woody plants, citing many previous works, including his own; Klimeš et al. (1997) further elaborated on the general features of clonality; and Windisch et al. (2008), who described a type of clonal growth of fallen caudices of Dicksonia sellowiana in southern Brazil, which is very similar to the type found in many species of Vellozia spp. This is also the case of Alsophila setosa (Schmitt and Windisch 2006).

The author declares no conflicts of interest.

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

Amphibian skin bacteria are important for host health by protecting against pathogens, but communities can vary greatly among host populations, influenced by environmental factors, habitats, and ecological interactions. Understanding this variation is key to studying how amphibians adapt and remain healthy across diverse environments. In this study, we sampled skin bacteria on coquí frogs (Eleutherodactylus coqui) from two sites in each of two regions: Puerto Rico, where they are native, and Hawaii, where they are introduced. We tested the hypothesis that bacterial communities differ between regions but are relatively more similar within each region. We also expected that comparing bacteria at the genus level would show more similarity than at the level of unique sequences, indicating the importance of microdiversity and functional roles. Beta diversity provided mixed support for these hypotheses, showing differences between sites that became less pronounced within each region at the bacterial genus level. Interestingly, one Hawaiian site stood out as distinct in multiple analyses. Despite predicted variation, we expected to find core (prevalent) bacteria shared across sampling locations, which was confirmed for a few taxa, suggesting they play important functional roles and may be selected by the host. Microbial community variation on coquí frogs is influenced by their habitat-generalist nature, with habitat likely affecting environmental bacterial sources, but can also be shaped by invasion history, disease, development stages, and season. This research enhances our understanding of how environmental and biological factors shape amphibian microbiomes, which is valuable for conservation efforts and studying invasive species.

Eco-labels are effective financial tools for implementing biodiversity-based land management near protected areas. When eco-labels market flagship species conservation, it is essential to ensure that these species also serve as umbrella species, benefiting broader biodiversity. This study assessed the potential of flagship species, chimpanzees and elephants, to act as umbrella species by analyzing their co-occurrence with other species and evaluating species-specific responses to anthropogenic pressures. Using 61,348 camera trap clips and illegal activities recorded during 4 years in Sebitoli protected forest (Kibale National Park, Uganda) surrounded by a highly anthropized landscape, we built a joint Species Distribution Model for chimpanzees, elephants, and 29 other taxa, including five threatened taxa. The co-occurrence matrix showed that chimpanzees and elephants were respectively co-occurrent with 26 and 20 other taxa, including respectively four and three threatened taxa. The intensity of illegal activities targeting wildlife (snaring) was significantly negatively impacting the detection of 18 of the taxa studied, including chimpanzees and elephants and three other threatened taxa. The intensity of illegal activities targeting flora had a significant negative impact on the detection of eight taxa, including elephants. Co-occurrence patterns supported the potential umbrella species role of chimpanzees and elephants through the shared benefits of their habitat conservation. Results allowed us to recommend the reduction of illegal activities, especially snaring, as a relevant shared conservation action to promote within future label standards. Although chimpanzees co-occurred with more species than elephants, elephants appeared as better surrogates for anthropogenic threats than chimpanzees, underlining their complementarity as umbrella species.